The present invention relates to a module comprising high and low pressure hydraulic accumulators for a hybrid vehicle, and a hybrid vehicle comprising such module.
Certain hybrid vehicles have an internal combustion engine which drives a hydraulic pump to recharge accumulators with pressurized fluid in order to store energy, and hydraulic motors supplied by these accumulators driving the traction wheels of the vehicle. These vehicles also comprise a hydraulic pump connected to the traction wheels, in order to recuperate the kinetic energy of the vehicle during braking and to recharge the accumulators.
The hydraulic accumulators may comprise in particular a high pressure accumulator receiving pressure from the hydraulic pumps in order to supply the motors, and a low pressure accumulator receiving the fluid returning from these motors.
These hybrid vehicles optimize the operation of the combustion engine by reducing its fuel consumption and emissions of polluting gas. With the stored hydraulic energy, the vehicle can drive in strictly hydraulic mode called “ZEV”, without emission of polluting gas, while the combustion engine is stopped.
A known type of hydraulic motor, specifically disclosed in document FR-A1-2972682, comprises a rigid assembly containing the pressure accumulators, the hydraulic command block and the hydraulic traction motors, which are all mounted together.
A particular configuration presented in the document comprises traction motors installed on the front axle, which are mounted to the hydraulic command block and a first reservoir installed longitudinally under the vehicle, while the second reservoir is mounted transversally behind the first reservoir.
One problem posed by this particular configuration is that the rigid assembly is not easily adaptable to a hybrid vehicle with a combustion engine in front and a fuel tank installed under the rear passenger seats, which is the conventional platform of a vehicle with a combustion engine only.
In particular, the front part comprising the hydraulic command blocks and the first reservoir installed longitudinally under the vehicle requires significant modification of the platform of this vehicle, and takes up part of the space reserved for the fuel tank, significantly reducing its capacity.
In addition, this rigid assembly extending over most of the length of the vehicle poses important problems of passenger safety, in particular in case of a frontal or lateral collision at high vehicle speed.